By Mohammed Mainuddin, Riasat Ali, S.M. Shah-Newaz, Christian Roth Revitalizing the Ganges Coastal Zone Conference 21-23 October 2014, Dhaka, Bangladesh http://waterandfood.org/ganges-conference/

1. Water
resources
in
the
coastal
zone
of
Bangladesh:
constraints
or
opportuni6es
for
cropping
intensifica6on?
CSIRO
LAND
AND
WATER
FLAGSHIP
Mohammed
Mainuddin,
Riasat
Ali,
S.
M.
Shah-­‐Newaz,
Chris5an
Roth
November
2014

2. Southern
Bangladesh
–
coastal
zone
• 19
Districts,
46,
271
Km2,
31
percent
of
the
country
• About
13,000
Km2
protected
by
123
polders
• Popula5on
–
40
million
(2010)
• Annual
rainfall
is
slightly
higher
than
the
remaining
area
of
the
country
• Most
vulnerable
to
climate
change
2
|
0
500
1000
1500
2000
2500
3000
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
Rainfall,
mm
Coastal
region
Non-­‐coastal
region

3. • Natural
calami5es
–
cyclones,
storm
surge,
floods,
water
logging,
etc.
• Shortage
of
fresh
water
–
both
for
drinking
and
irriga5on
water
• Affected
by
salinity
• Cropping
intensity
is
low
• Large
fallow
lands
during
Rabi
–
due
high
salinity
and
lack
of
water
• As
of
2005,
65
%
popula5on
are
below
poverty
line
compared
to
the
40%
at
the
country
level
Issues
in
the
coastal
zone
3
|

4.
GoB
is
giving
importance
to:
• to
intensify
agriculture
in
the
coastal
zone
• to
make
the
zone
environmentally
sustainable
Key
ques6ons
4
|
The
ques5ons
are:
Is
there
scope
for
sustainable
cropping
intensifica5on?
What
are
the
constraints
and
opportuni5es?
Water
resources:
constraints
or
opportuni5es?

5. The
main
objec5ve
was
to
iden5fy
the
opportuni5es
and
constraints
to
the
sustainable
intensifica5on
of
cropping
systems
in
the
coastal
regions.
Done
in
2012-­‐13
ACIAR
funded
scoping
study
5
|

6. • Complex
river
network-­‐
57
cross
boundary
rivers
• Confluence
of
the
Ganges,
Brahmaputra,
and
Meghna
Rivers
• Total
annual
discharge
is
1,200
–
1,500
billion
m3
• High
seasonal
varia5on-­‐
too
much
in
the
wet
season
and
too
lidle
in
the
dry
season
• No
big
storage
facili5es
Surface
water
resources
6
|
Daily
discharge
at
the
Hardinge
Bridge
on
the
Ganges
River

7. • Availability
depends
on
the
flow
at
the
Ganges
and
the
Brahmaputra
• Dry
season
flow
at
the
Gorai
river
is
very
important
for
salinity
in
surface
water
• Availability
is
decreasing
due
to
increasing
upstream
use
Surface
water
availability
–
coastal
zone
7
|
-­‐1000
0
1000
2000
3000
4000
5000
6000
1/01/1999
1/01/2000
1/01/2001
1/01/2002
1/01/2003
1/01/2004
1/01/2005
1/01/2006
1/01/2007
1/01/2008
1/01/2009
1/01/2010
Discharge,
m3/s
Discharge,
m3/s
Discharge
of
the
Ganges
at
Hardinge
Bridge
Discharge
at
Gorai
Railway
Bridge

8. • GoB
recently
spent
millions
to
increase
the
flow
to
the
Gorai
river
by
dredging
the
Gorai
oeake
• Dredging
has
increased
dry
season
flow
which
reduces
salinity
of
surface
water
Surface
water
availability–
Gorai
restora6on
8
|
0
500
1000
1500
2000
2500
Discharge,
m3/s
Discharge
at
Gorai
intake
after
dredging
0
4
8
12
16
20
1-­‐Jan 31-­‐Jan 1-­‐Mar 31-­‐Mar 30-­‐Apr 30-­‐May 29-­‐Jun 29-­‐Jul
Salinity
(ppt)
Salinity
observed
at
Khulna
during
different
year
Year
2012 Year
2011 Year
2010 Year
2009 Year
2007

9. Considerable
increase
in
salinity
over
5me
both
in
concentra5on
and
area;
saline
front
moved
further
inland
through
the
stream
Surface
water
salinity
9
|

10. Presenta5on
5tle
|
Presenter
name
Groundwater
resources
10
|
Aquifer
systems
in
Khulna
Pre
and
post
monsoon
groundwater
surfaces,
2010

11. • WL
–
steady
or
rising
except
some
wells
in
in
the
upper
part
and
in
Noakhali
• Scope
for
freshwater
storage
in
the
aquifer
by
pumping
saline
groundwater?
Groundwater
trend
11
|
Noakhali
Narail

12. Groundwater
salinity
12
|
6
m
52
m
2011
2012
•
Salinity
is
varying
in
groundwater
–
with
5me
and
depth
• There
may
be
opportuni5es
for
limited
irriga5on
–
but
need
more
study.
Source:
BADC

13. Presenta5on
5tle
|
Presenter
name
Irriga6on
–
net
requirements
by
major
crops
13
|
Average
irriga5on
requirements
of
different
crops
• Net
irriga5on
requirement
for
non-­‐rice
crops
is
not
very
high.
• Many
rabi
crops
can
be
grown
with
1
or
2
strategic
irriga5on.
• Scope
for
rabi
cropping.

14. Salinity
trial
of
wheat
Layout
of
all
salinity
trials:
this
one
is
Benerpota,
Satkhira
28
plots
deep
x
4
replica6ons
=112
plots:
note
salt
on
surface
and
adjacent
lake
4
loca5ons
–
Satkhira,
Patuakhali,
Barguna,
Noakhali

15. Grain
yield
of
each
plot
against
its
plot
salinity
for
the
whole
Satkhira
site
(112
plots)
–
Salinity
measured
1
month
aer
sowing
y
=
-­‐1.6568x
+
4.6653
r²
=
0.10
0.0
1.0
2.0
3.0
4.0
5.0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Grain
Yield
(t/ha)
Soil
salinity
(av
0-­‐90
cm
EC
1:5
dS/m
For
ECe
mul6ply
by
10)
Salinity
trial
of
wheat

16. Constraints
and
opportuni6es
While
there
are
constraints
of
salinity
and
availability
of
freshwater
for
irriga5on
there
are
opportuni5es
as
well.
Some
of
these
are:
• Collec5on,
use
and
management
of
fresh
surface
water,
beder
polder
management.
• Sustainable
use
of
groundwater
in
conjunc5on
with
stored
surface
water
for
strategic
irriga5on.
• planning
of
the
crop
calendar
to
use
residual
moisture.
• Improved
agronomic
management
prac5ces.
Presenta5on
5tle
|
Presenter
name
16
|
Need
an
integrated
approach

17. Proposed
project
funded
by
ACIAR
(2015-­‐19)
Cropping
systems
intensifica5on
through
integrated
soil,
water
and
crop
management
in
the
salt
affected
coastal
zone
of
Southern
Bangladesh
and
South-­‐eastern
West
Bengal,
India.
• Develop
regional
scale
understanding
of
the
surface
water
and
groundwater
resources.
• Develop
a
detailed
understanding
of
the
salt
and
water
dynamics
at
the
polder/sub-­‐regional
scale
including
evalua5on
of
groundwater
resources,
salt
movement,
surface
water
• Develop
detailed
understanding
of
crop
produc5on
responses
to
various
improved
polder
and
fresh
water
management
strategies,
through
experiments,
field
trials
and
crop
systems
modelling.
• Test
suitable
cropping
op5ons
and
water
and
salt
management
through
a
par5cipatory
approach
of
field
evalua5on
and
co-­‐learning.
• Pilot
some
up-­‐scaling
prac5ces
for
sustainable
intensifica5on.
Presenta5on
5tle
|
Presenter
name
17
|

18. CSIRO
Land
and
Water
Flagship
Mohammed
Mainuddin
Senior
Research
Scien5st
Water
Resource
Management
Program
t
+61
2
6246
5929
e
mohammed.mainuddin@csiro.au
w
www.csiro.au
CSIRO
LAND
AND
WATER
FLAGSHIP